Automatic control for stone cutting and finishing machines



Nov. 10, 1931. ELLENBECKER 1,831,412

AUTOMATIC CONTROL FOR STONE CUTTING AND FINISHING MACHINES Filed Nov. 14, 1929 3 Sheets-Sheet 1 l? ZJLLQYZW Nov. 10, 3 J. P. ELLENBECKER 1,831,412

AUTOMATIC CONTROL FOR STONE CUTTING AND FINISHING MACHINES Filed Nov. 14, 1929 3 Sheets-Sheet 2 Nov. 10, 1931.

J. P. ELLENBECKER JXUTOMATIC CONTROL FOR STONE CUTTING AND FINISHING MACHINES Filed Nov. 14, 1929 3 Sheets-Shae t 3 Patented Nov. 10, 1931 UNITED STATE-SF Jon r. or snot-'ounrirmwnse'rn Application :filed INovemberr14, 19292e Seriat No. 407,111.:

My present invention relatesxb roadly, to

tively easy while cuttingof suriacesnotpan allel thereto has been very difficult and is usually performed-by hand. Therdifliculty noted was found in the fact thatthe cutting:

tool, motor and supporttherefore were very;

heavy makingit difiicult. and'expensive to operate to cut serpentine:surfacesby theuse of a direct-acting template. The use of'a" template heretofore necessitated the discon+ necting of the motor and cutting tool support from its raising and loweringinechanisln and the supporting thereof directly on the tern-- plate. In view of the heavy load the template was required to carry, it was necessary to make the same very heavycand strongcand' the expense thereof was such thata template was only used when a relatively large number of duplicate parts were to bemade, and even when provided the usethereof encoun-v tered many difiiculties. Furthermore, agreat deal of power was required to movethe template in respect to the cutting or finishing tool to raise the load supported on the platen.

The machine illustrated in whichlmypresent invention is embodiedemploys a raising and lowering device, that is a device for vary-- ing, setting and controlling the movement of acutting or finishing tool toward and'fro'rn the work carried on a movable platen and operated by a reversible variable speedelectric motor. In connection with this electric inotor I provide a. novel differentially-acting, controlling device whereby, the electric-mo tor will be operated intermittently at variable speeds in either direction under the control. of a very light and inexpensive template mov able with the platen andoperative to-iraise, lower or otherwisevarytheposition of the cutting or finishing toolin respect to the work accordingto'the curved, straighter irregular nental and building stone andthelike; These stones are quite generally cut by the use Ora. motor-driven cutting or finishing.tool and the-r problem of cutting straight orfflatsurfaces parallel to the line of feed has been compara line that it isndesired to cuti and i which is, represented by the template. This :difi'ren- I tiali motor?controllingdevice illustrated in the drarwingsandl 'hereinaft'er. described; involves a plurality oflsp aced; contacts connectedi-toonexside o1" the lnotor circuitand co operatingt novablncontact .connectedvto the OtllBX SiCtG of the motor circuit. the: movement of which is actuated bythe template to CO11-1- trol the forming of the curve. or... irregular 3 surface 'llorprovidfOr-the cutting ofsurr faces that .rise and fall, the spaced contacts: ofithe motorlcircuit arearranged infltwolines or series and." are. cooperatively} arranged inn respecttoxthemovable contactiormthe-cutting otsuch surfaces under thecontrol 'ioflarprop erly',designedfltemplatea The. invention further rprovidesother; ims. p ortant andlnovelf featuresynas will herein: after,appea1-.;. a

Tosther aboverendj generally. stated; theainvention-consists oiithe novel devicesandicoms binations of deviceshereinafter describedandj' defined in the claims. d

In: i-th'eaaccompanying drawings, which .il lustrate the-3 invention, like characters indicatelike parts throughout. the several? views.

Referring tozthedrawings FigeI-is aafront elevationof'astone cutting; machinehaving; the invention. embodied; therein; a I g Y 1 Fig 2His planaview ofdthez diiferentially motor; controlling, device on i an, enlargeclf scale;

is F zig tisia.-viewpartly---in. side elevation and partlyyin section taken I on the irregular line. 34-3-ofEig,;2 .with.the tracer wheel indicated brokertlines and further: .frag nentaril y il lustrating;. a platen vbyaneans of broken lines and;the1te1nplate inside elevation A ds a view partly in elevation and]. partly} in; section taken on :the linev 4 .4 oft 3;, a

,Fig 51 -is*-a. -viewe partly, in elevation; andl' partly in section taken .on" the line 5--51of F g-fit g Fig isadtailview principally in section takenflontheirregular linet6'6' of Fig. 4.; and? 1 Fig T'is a wiring diagram.

The numeral 7 indicates a base supported on and rigidly secured to a bed 8 and on which base a reciprocating platen or work table 9 is mounted. This work table 9 has on its under side a pair of rails 10 which rest in spoollike rollers 11 journaled on the base 7. To reciprocate the work table 9 there is provided an electric motor 12 which drives a gear 13 journaled on the base 7 and meshing with a rack 14 on the under side of said table. In the driving connections from the motor 12 t0 the gear 13 is avariable speed transmission mechanism diagrammatically illustrated and indicated, as an entirety, bythe numeral 15. The direction of travel of the work table 9 may be reversed either by the motor 12 or the transmission mechanism 15. On the right hand side of the work table 9 is an upstanding longitudinally extended flange 16 for a purpose that will presently appear.

Mounted on the bed 8 at the right side of the base? is a heavy fixed upright post 17 having vertical ways 18 on which a horizontal cross rail 19 is mounted for parallel raising and lowering movements over said base. This cross rail 19 is held substantially counterbalanced by a weight 20 and is raised and lowered by a long vertical feed screw 21 ournaled at its ends in bearings on the post 17 and works in a nut-acting member 22 secured to the cross rail 19 and held against rotation. An electric motor 23 is provided for operati'ng the feed screw 21 and has on its armature shaft a miter pinion 24 which meshes with a miter gear 25 on the upper end of a short shaft 26 journaled in a bearing on the post 17. A spur pinion 27 on the shaft 26 meshes with a spur gear 28 on the upper end of the feed screw 21.

A variable speed transmission mechanism diagramamtically illustrated by the numeral 23 is interposed between the gear 25 and pinion 27 for varying the speed of the raising or lowering of the cross rail 19 in respect to the travel of the work table '9. The trans-' mission mechanism 15 permits the speed of the work table 9 to be varied in respectto the speed at which the cross rail 19 may be raised or lowered.

A saddle 29 is mounted on the cross rail 19 for horizontal sliding movement and attached thereto is a swivel 30 the axis of which is horizontal and extends parallel to the line of travel of the work table 9. Journaled in the swivel 30 is a spindle 31 to which is secured a tool head 32. The spindle 31 is driven by an electric motor 33 carried by the swivel 30. Said swivel 30 is turned about its axis by means of a segmental rack 34 on the saddle 29 and a cooperating pinion 35 which may be operated, at will, by a hand wheel 36: Secured to the toolhead 32 is a grinding wheel 37. The saddle 29 is moved back and forth on the cross rail 19by a cross feed screw 38 journaled in hearings on said cross rail and works in a nut-acting member, not shown, on said saddle. A hand-crank 39 is provided for operating the cross feed screw 38.

By turning the feed screw 21 the cross rail 19 may be raised or lowered, and hence, the grinding wheel 37, and by operating the cross feed screw 38 the saddle 29 may be moved back and forth on the cross rail 19 to axially adjust said grinding wheel transversely of the feed table 9. The swivel 30 may be turned about its axis by manipulating the hand wheel 36 to move the grinding wheel 37 in the arc of a circle between vertical and horizontal positions. 7

The electric motor 23 may be of any reversible variable speed type for either direct or alternating currents of standard voltage and frequency. There is illustrated in the drawings a three phase alternating current motor of the slip ring type. The lead wires 40 of said motor are connected to power sup-' ply wires 41 by a magnetic reversing switch 42 and the speed of said motor is controlled by a series ofresistances 43, as shown two, in an induced secondary three phase circuit 44 that leads from the motor 23. Two relays 45 is a circuit 46 of a lower voltage than the power circuit 41 are provided for shunting the current around one or both resistances 4.3 to increase the speed of the motor 23. Two electro magnets 47 in the circuit 46 are provided for operating the reversing switch 42 and interposed in said circuit is a hand operated double-throw multiple switch 48 for manually controlling the reversing switch 42 and when said double-throw switch is in neutral position the reversing switch 42 is open. Also interposed in the circuit 46 is'a hand controller 49 for closing the circuit 46 to energize either one of the magnets 47 for reversing the motor 23 and to energize either one or both of the relays 45 for shunting the circuit around either one or both resistances 43 to vary the sped of the motor 23.

An automatic magnetic brake 50 is provided for the motor 23 and the circuit of its magnet 51 is indicated by the numeral 52 and leads from the motorfed circuit 40. As is well known, this type of brake 50 will automatically release when the motor circuit 40 is closed by the reversing switch 42 and will set when said circuit is open,thus preventing the motor 23 from being operated by momentum.

Referring now in detail to the automatic differentially-acting controlling device, the numeral 53 indicates a plurality of spaced relatively fixed contacts and the numeral 54 indicates a cooperating movable contact. Said fixed contacts 53 are arranged in two series cooperatively arranged one on each side of neutral position of the movable contact 54. These contacts 53 and 54 are mounted in a box-like casing 55 having a displaceable cover and the body'of said casing is rig- 1 v sesame idly secured to a crossliead' 5dmounted'in' wayson a relatively fixed -support "57. This support 57 is mounted onaheavy' depending bar 58- secured to 'the under side of the cross rail 19-betweenthe fi'angel6 and post 17 'and holds thecasing above said fiange. The

support 57 is secured 'to'the bar58 for vertical adjustmentby nut-equipped bolts 59' which extend through holes in;theupper and lowerends of'said support and vertical slots in said bar.

To vertically adjust the casing=55 on its:

support 57 there-is provideda micrometer screw rod 60 journaledfin bearings on the support 57 and works in a nut-acting memb'er' 61 rigidly secured to the cross-head 56 and having in itsupper-end a turning pin 62' by through the casing 55- and secur ed to thesides thereof.

The two series of 'fi'xe'd contacts 53 are spaced the one above theother with themo'vable contact 54 extending horizontally therebetween. This movable contact 545 as shown, is in theform of a flat finger; rigidly secured to'and between a pair of spaced insulating;

members 63, which, in turn, are=rigidly se-. cured to the outer end'of a horizontal arm 64 pivoted to the cas1ng55 for vertioalmovement to carry the movable contact 54 into engagement with the contact53 of eitherseries. It is important to note, by reference to Figs.

3, 5 and 7 that the movablecontaet 54 when in neutral position is midway between the two series of contacts 53 and out ot'contact therewith. It is also important to note that the contacts 5305 each series are successively and progressively farther away from neutral position of the movable'contact 54, reading from the left to the ri ht in resoect t'o Fi' s- 5 and 7'.- Each contact 53" is yieldingly pressed toward themovablecontact 54 by a coiled spring 65 on a 'nut-equippedbolt.66

secured to a fixed stop plate 67 on one of the insulating members 55 and under the-respective contact 53. Theapproaching-move.

ment of each contact'53 toward the contact 54 islimited byan adjustable-screw 68 se'- cured to said contact 53 and normallyimpinging against the stop- -plate 67;

The two left-handcontacts 58 are provided for closing the circuits for the reversing the left-hand magnet 47 which'oper ates the switch 42 tojreverse= theranotor 23 for move? ment in a1 directiona toelevate the grinding,

wheel 373- Areverse or down-ward"move v ment of -the movable contact J 54 rwil'l engage the'lower left hand contact 53; close theci-rcuit 46; energizing.therightrhand magnet 47. which-operates the switchf42 to reverse the motor: 28 for rotation in the proper direction to lowerthe grinding wheel 37.

The two intermediate contacts. 53 are: con-'- nected to=the switch 48, the upper one by a wire 72 and the lower'one byra wire'73*and when the: movable contact 54is in engage-i ment 'with-weither one of said intermediate contacts, the left-hand relay 48: will be ener-i gized and operated to shunt the circuit around the left-handresistance 43 and thereby cause the motor to operate at intermediate speeds lVires 7 4 and= 75 connect the upper andlowerright-hand contacts; 53, respective. ly, to the-switch 48. When the movablecon tact 54is in engagement with either one of these r ght-hand contacts 53' the circuit 46 1s closed and the right-handrelay '45 energized and operated tothecircuit aroundthe right-r hand resistance 43 and therebycause the mo; tor 23 to operate at high speed.

It will be understood that when the-movable contact 54 is in engagement with either one of theleft-hand contacts 58' the motor 23' isoperating at low speed and when said-mov v ableconta'ct is movedinto engagement with; either one of the intermediate contacts-53 the-engagedleft-hand contact will yieldto. permit suchmovement and likewise the ein gaged intermediate contact 58will yieldto permit the movablecontact 54to engage onc of-the right-hand contacts'53.

The movable contact 54 is automatically ope'rated-bya tracer wheel 76 anda cooperat ing template 7'? onwhichsaid wheel isarrangedto run. This wheeli76 is journaled on a trunnion which erztendstransversely of the arm 64 and is rigidly secured-thereto, see Figs. 2 and 3. Said template77'is cut from a thin sheet of metal or other suitable material and isdetachably but rigidly secured to the flange 16 by nut-equipped bolts. '78 which extend through holes in said flange and vertical slots in said template.

A= counterbalancing spring 79 is provided forholdingthe tracer" wheel 7 (S substantial ly balanced to take the majority ofits weight from the template, but has suiiicient weight on said template to keep-the w-heel76'in-contact therewith so that the wheel 76 will closely follow the template 77'. This counter-balancing spring 79 'is held in an upright'tubu lar'housing 80011 the casing-:55, attached to the insulating members 63 andanchored to- .1

an'adjusting screw 81 in the top of said; housing. By adjusting the nut on'the screw 81 the tension ofthespring79niay be varied, at will; To steady the action; ot the movable contact 54 andprevent undue vibray Lil tions there is provided a dash pot 83 held suspended from the casing and its piston rod is attached to the insulating members 63.

Mounted on the feed table 9 is a stone the top of which is to be cut by the grinding wheel 37 to the shape of the template 7 7 The weight of this stone X is suflicient to hold the same in position on the work table 9.

It is now the general practice to cut a template in the drafting or designing room to be used by a stone cutter in shaping a serpentine or other irregular surface. By the use of my automatic controlling device the template is simply attached to the feed table 9 and the grinding wheel 37 automatically controlled thereby.

Operation tion one end of the stone under the grinding wheel 37 and the manually operated switch 48 set to cut out the automatic controlling device and connect the hand controller 49 in the circuit 46. This hand controller 49 is then operated to lower the grinding wheel 37 substantially into contact with the top of the'stone and thereafter the hand switch 48 is operated to cutout the hand controller 49 and connect the automatic controlling devices in the circuit 46 and the switch 48. The final manual adjustment of the grinding wheel 37 for the first cut to be made on the stone is performed by means of the micrometcrscrew rod which positions the automatic controlling device with its tracer wheel 76 resting on the straight end portion of the template 77 which corresponds to the same end of the stone over. which the grinding wheel 37 is positioned. In this position of the tracer wheel 7 6 the movable contact 54 is in neutral position and the brake 50, for the motor 23, set. To adjust the automatic controlling device onto stones that vary considerably in height the support 57 may be raised or lowered on the bar 58.

The motor 12 for driving the work table 9 is next started to move the stone under.

53 which completes the circuit 46 through the wires 69, 71 and switch 48, energizes the lefthand magnet 47 which operates the reversing switch 42 to cause the motor 23 to rotate in the proper direction to elevate the grinding wheel 37 by means of the feed screw 21. At

the time the circuit for the motor. 23 is closed.

the brake 50 is automatically released and said motor 1s operatlng at low speed.

Further lifting movement of the tracer wheel 76 by the curved portion of the tem-;

upper right-hand contact 53 and thereby through the wire 74 close the circuit 46 through the right-hand relay 45 which shunts the circuit 44 around the right-hand resistance 43 and causes the motor to operate at higher speed. Durin the lifting of the movable contact 54, the upper series of yielding contacts 53 are successively and progressively picked up by said movable contact and held thereby.

At the time the tracer wheel 7 6 moves over the crown of the template 77, the movable contact 54 will return to neutral position and at which time the upper series of contacts 53 will be progressively and successively released by the movable contact 54 in reverse order from that in which they were picked up thereby and cause the motor to drop from high speed to intermediate speed and from intermediate speed to low speed and as the movable contact 54 moves out of engagement with the upper left-hand contacts 53, the circuit of said motor is broken and the brake 50' automatically set to prevent the motor 23 from operating by momentum.

As the tracer wheel 76 moves downward on the curved portion of the template 77 the lower series of contacts 53 are engaged by the movable contact 54 in the same manner that the upper series of contacts 53 were engaged thereby and the action of reversing the motor and shunting the circuit 44 around the resistance 43 is also the same as that previously described except that the screw :21 is rotated in a reverse direction to lower the grinding wheel 37.

From the curved portion of the template 77 the tracer wheel 76 moves onto the rear straight end portion of said template and thereby causes the movable contact 54 to progressively release the lower series of contacts 53 in reverse order from that in which they were picked up and progressively decrease the speed of the motor 27 and finally open the circuit of said motor and set the brake 50 to prevent said motor from operating by momentum.

To make a second out over the top of the stone, the automatic controlling device is manually lower-erh'say one-sixteenth of an inch by the micrometer screw rod 66, and the direction of travel of the work table 9 reversed so that the stone will be cut in an opposite direction from that in which the first cut was made but in the same manner. This adjustment of the automatic controlling device may be repeated until the stone is cut to the proper shape.

Any desired number of contacts 53, which correspond with the intermediate and righthand contacts 53, may be used so that there will be considerable variation in the speed of the motor 23. For each pair of contacts 53 added, it will be necessary to add another resistance and correspondingly modify the switch 48 and hand controller 49. Various different kinds of cutting, grinding and finishing tools may be employed during the cutting of stone and while the invention is shown embodied in a stone cutting machine, the same is equally well adapted for use where similar cut-ting action takes place. In the preferred arrangement of the apparatus illustrated, the maximum. raising and lowering of the grinding wheel 37 is substantially that of the travel of the work table 9.

In some instances it might be desirable to provide a template in which it is necessary for the tracer wheel 7 6 to travel under the same rather than over the template as shown. In such a modification the spring 7 9 may be adjusted to cause the tracer wheel 76 to be lifted into contact with such a template.

The position of the tracer wheel 7 6 on the arm 6ft is such that very slight vertical movement imparted to said wheel by the template '77 will. materially increase the movement of the contact so that slight changes in the angle of said template will cause the movable contact 5st to pick up or release the contacts to vary the speed of the motor 23, and hence, the speed at which the grinding wheel 37 is moved vertically toward or from the,

won: without stopping the motor 23, thus causing the grinding wheel 37 to out true curves or inclined surfaces.

In place of feeding the stone horizontally to a cutting tool, the mechanism may be modified to feed said cutting tool horizontally to the work or the stone may be moved vertically into or out of engagement with the cutting tool.

What lclaim is:

1. The combination with two cooperating members one of which is a work support and th other of which is a tool, one of said members being mounted for raising and lowering movements and a mechanism for raisingaand lowering the same including. a reversible: variable speed motor, one of said members being mounted for horizontal movement, 'of. an automatic differentially-acting controlling device for intermittently operating the-motor in eitherdirection at variable speeds .anda template, one of which is on the member mounted for horizontal movementand the other of which is relatively stationary, saidcontrolling device having .an actuating. tracer controlled'by the template. .2.'.The combination with a verticallymovable tool, mechanism for raising and lower ing the tool including a reversible variable 'speedumotor, a traveling work table, and means foroperating the table for'feeding theworkthereon to. the tool, of a template on the-work table, .and :an automatic di tferentially-acting controlling device for inter- :mittently operatingthe motor. in eitherdirectionat-variable speeds and having an actuating tracercontrolled by the template. -.3.lThe structure defined in claim 2 in which the controllingdevice is adjustable inrespect tothe template to varythe position of the. tool .in respectto the work. .4. .Thecombination with a vertically movable tool, mechanism for raising and lowering the tool. including a reversible motor, a reversing. switch and resistance in the motor .ci-rcuit,.a traveling work table, and m eansfor operating the table for feeding work-thereon to the tOOLofate-mplate onthe work table, a magnetically operated differentially-acting controlling device for operating the 1 switch and for progressively varying the resistance to chair-naev the speed ofthe motor and includingafplurality .of spaced contacts and a cooperating movable contact, said spaced contactsjbeingiarranged in two series cooperatively arranged .oneon each side of neutral position of-the i-movable contact, and an actuating tracer for the movable contact controlled ,by the template.

.5. The structure defined in claim 4 in which thespaced contacts are yieldingly pressedtoward-the movable contact, and in which the spaced contacts in each series are successively and progressively normally spaced farther away from neutral position of the movable relatively stationary, said controlling device includes a plurality of spaced contacts and a cooperating movable contact, said'controlling device having an actuating tracer controlled by the template, said movable contact being arranged to engage or release the spaced contacts progressively and differentially according to the vertical pitch of the template.

7. The combination with two cooperating members one of which is a work support and the other of which is a tool, one of said members being mounted for raising and lowering movements and mechanism for'raising and lowering the same including a reversible variable speed electric motor, the other of said members being mounted for horizontal movement, of an automatic differentiallyacting controlling device for operating the motor in either direction and at variable speeds and a cooperating template, one of which is on the member mounted for horizontal movement and the other of which is relatively stationary, said controlling device includes a plurality of spaced contacts and a cooperating movable contact, said spaced contacts being arranged in two series cooperativelv arranged one on each side of neutral position of the movable contact, said controlling device having an actuating tracer controlled by the template, said movable contact being arranged to engage or release the spaced contacts of each series progressively and differentially according to the vertical I pitch of the template.

8. The combination with two cooperating members, one of which is a work support and the other of which is a tool, one of said members being mounted for raising and lowering movements, and power means for raising and lowering the same at variable speeds, one of said members being mounted for horizontal movement, of an automatic difierent-iallyacting controlling device for intermittently 7 operating the power means in either direction at variable speeds and a template, one of which is on the member mounted for horizontal movement and the other of which is relatively stationary, said controlling device having an actuating tracer controlled by the template. 1

In testimony JOHN P. ELLENBECKER.

whereof I afiix mv signature. I 

